Oil composition with mono-acylglycerides

ABSTRACT

The present invention relates to a process for preparing a deodorized oil with in-situ prepared mono-acylglycerides and the oil obtained as such. It relates to a process for preparing a deodorized oil containing in-situ prepared mono-acylglycerides by interesterifying in presence of an enzyme a glyceride containing fraction wherein the ratio of free and esterified hydroxyl groups (OH) to free and esterified fatty acids (FA) is greater than 1.07 and obtaining an oily composition containing less than 1% w/w, preferably less than 0.5% free fatty acids. Furthermore it relates to a deodorized oil containing 30 to 70% triglycerides, 20 to 50% di-acyl glycerides, 1.5 to 25% mono-acyl glycerides.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of European Patent ApplicationSerial No. 15170026.7 filed Jun. 1, 2015, entitled “OIL COMPOSITION WITHMONO-ACYLGLYCERIDES”, and European Patent Application Serial No.15198671.8 filed Dec. 9, 2015, entitled “OIL COMPOSITION WITHMONO-ACYLGLYCERIDES”, which applications are hereby incorporated byreference herein in their entirety

FIELD OF THE INVENTION

The present invention relates to a process for preparing a deodorizedoil with in-situ prepared mono-acylglycerides and the oil obtained assuch.

BACKGROUND OF THE INVENTION

Many familiar foods exists as emulsions at least at some stage duringtheir production. These foods include processed foods such as cream,margarine, fruit beverages, soups, cake batters, mayonnaise, sauces,desserts, ice cream, just to name a few of them. The overall quality ofa particular emulsion-based food product is determined by a combinationof physicochemical and sensory characteristics, such as appearance,aroma, taste, shelf-life, texture but also other features such aslabeling give a certain perception to the consumer.

One class of frequently used food emulsifying agents includes themono-acylglycerides (MAG). They are typically based on fats and oilssuch as sunflower, palm or soybean oils.

It would be desirable to have a process which allows the preparation ofan emulsifying oil without adding foreign material.

The current invention provides such a process.

SUMMARY OF THE INVENTION

The current invention relates to a process for preparing a deodorizedoil containing in-situ prepared mono-acylglycerides wherein the processis comprising the following steps:

-   -   a) Hydrolysing a triglyceride oil with water in presence of an        enzyme and obtaining an hydrophobic phase wherein up to 50% w/w        of free fatty acids are formed,    -   b) Removing from 20% to 100% w/w of the formed free fatty acids        for maintaining a glyceride containing fraction wherein the        ratio of free and esterified hydroxyl groups (OH) to free and        esterified fatty acids (FA) is greater than 1.07,    -   c) condensing and/or interesterifying in presence of an enzyme        the glyceride containing fraction, and    -   d) collecting a deodorized oil containing less than 1% w/w,        preferably less than 0.5% free fatty acids and containing from        1.5 to 25% mono-acyl glycerides.

It further relates to a deodorized oil containing 30 to 70%triglycerides, 20 to 50% di-acyl glycerides, 1.5 to 25% mono-acylglycerides and less than 0.1% free fatty acids.

DETAILED DESCRIPTION

The current invention relates to a process for preparing a deodorizedoil containing in-situ prepared mono-acylglycerides wherein the processis comprising the following steps:

-   -   a) Hydrolysing a triglyceride oil with water in presence of an        enzyme and obtaining an hydrophobic phase wherein up to 50% w/w        of free fatty acids are formed,    -   b) Removing from 20% to 100% w/w of the formed free fatty acids        for maintaining a glyceride containing fraction wherein the        ratio of free and esterified hydroxyl groups (OH) to free and        esterified fatty acids (FA) is greater than 1.07,    -   c) condensing and/or interesterifying in presence of an enzyme        the glyceride containing fraction, and    -   d) collecting a deodorized oil containing less than 1% w/w,        preferably less than 0.5% free fatty acids and containing from        1.5 to 25% mono-acyl glycerides.

It should be noted that all percentages are expressed as weightpercentage, unless otherwise explicitly mentioned.

Furthermore the ratio of (OH) to (FA) each time refers to the ratio of(free and esterified hydroxyl groups (OH)) to (free and esterified fattyacids (FA)), unless otherwise explicitly mentioned.

The triglyceride oil can be selected from the tropical oils, palm oil,palm kernel oil and coconut oil, or babassu oil, and/or theircorresponding fractions. Furthermore, the triglyceride oil may also berapeseed oil, canola oil, sunflower oil, high oleic sunflower oil,soybean oil, corn oil, peanut oil, walnut oil, hazelnut oil, olive oil,camelina oil, linseed oil, hemp oil, safflower oil, cottonseed oil andvarieties of these oils having altered fatty acid compositions such ashigh oleic, low linolenic or low saturated oils (e.g. high oleic canolaoil, low linolenic soybean oil or high stearic sunflower oil), andmixtures of one or more thereof.

Preferably sunflower oil, rape seed oil, palm or soybean oils, morepreferably palm stearin is used as the triglyceride oil for thehydrolysis.

The enzymatic hydrolysis of the triglyceride oil is performed inpresence of water and enzyme and thus forming a system consisting of ahydrophilic liquid phase (water) and a hydrophobic liquid phase. Thereis no need for the addition of glycerol and/or low aliphatic esters. Theenzyme can be present in the hydrophilic phase or it is immobilized on acarrier. Hydroxyl groups get enriched in the hydrophilic phase, whilefatty acids get enriched in the hydrophobic phase. The hydrolysis iscontinued until a content of up to 50% w/w of free fatty acids isobtained in the hydrophobic phase.

The removal of the formed free fatty acids is generating the glyceridecontaining fraction having a ratio of hydroxyl groups (OH) to fattyacids (FA) of greater than 1.07. This removal can be done in manydifferent ways. From 20% to 100 weight % of the formed free fatty acidscan be removed, depending upon the applied method. In fact, the freefatty acids can be decanted, neutralized and/or distilled off.

Decantation will allow to remove 20 to 80% w/w of the excess of freefatty acids, thus leaving a system of hydrophobic and hydrophilic phaseenriched in hydroxyl-groups, which corresponds to the glyceridecontaining fraction wherein the ratio of hydroxyl groups (free oresterified OH) to fatty acids (free and esterified fatty acids FA) isgreater than 1.07. This glyceride containing fraction is furthercondensed and/or interesterified to prepare a deodorized oil rich inmono-acylglycerides and deficient or containing less than 1% w/w,preferably less than 0.5% free fatty acids. In practice, this can forinstance be achieved by removing water under vacuum in presence of theenzyme, and potentially having an additional reaction time of from 1 to36 hours.

In another aspect of the invention, 20 to 100 weight % FFA is removed bydeodorization, distillation or short path evaporation. Deodorization isexplained below and short path evaporation is a distillation technologythat involves the use of a distillation equipment wherein the distillateis travelling over a short distance, often only a few centimetres, andit is normally done at reduced pressure. The advantage of thisdistillation technology is that the heating temperature can beconsiderably lower (at reduced pressure) than the boiling point of theliquid at standard pressure, and the distillate only has to travel ashort distance before condensing. A short path distillation furtherensures that little amount of product is lost on the walls of theequipment. The short path evaporation is performed at a temperature offrom 150° to 210° C.

In yet another aspect of the invention, the free fatty acids can also beneutralized by means that are commonly known, such as washing out orprecipitating with alkali, earth alkali salts, preferably sodium orcalcium salts. The remaining fraction (after the removal of the freefatty acids) is in each aspect of the invention, the glyceridecontaining fraction having a ratio of hydroxyl groups (OH) to fattyacids (FA) of greater than 1.07.

By removing the formed free fatty acids by neutralisation ordistillation, the residual fraction is condensed for obtaining aglyceride containing fraction with less than 1% of free fatty acids andmore than 1% of mono-acylglycerides.

Alternatively, a hydroxyl enriched fraction (is glyceride containingfraction having a ratio of hydroxyl groups (OH) to fatty acids (FA) ofgreater than 1.07) can be obtained by starting with a commerciallyavailable oil containing significant amounts of di-acyl-glycerides(DAG), such as from 5 to 15% of DAG, and whereby a distillation processis used to enrich DAG in the distillate fraction. The distillation canbe a (regular) distillation, deodorisation or short path evaporation.The distillate fraction is the glyceride containing fraction having aratio of hydroxyl groups (OH) to fatty acids (FA) of greater than 1.07.An appropriate example might be a DAG fraction from palm oil obtainedthrough the short path evaporation of palm oil.

The distillate (e.g. from the short path evaporation), which is theDAG-rich fraction containing at least 20% w/w of di-acyl-glycerides(DAG) is further used in the condensation and/or interesterificationstep.

Without being bound to a specific and/or limited scientific explanationit is hereby understood that the in-situ preparation of the currentinvention which occurs in presence of water has certain advantages overexisting processes that are based upon glycerolysis in presence ofmethyl esters or addition of glycerol. The current invention does notneed the addition of methyl esters, low aliphatic alcohols and/orglycerol and there is no need for glycerol labelling and no need forextra supply of glycerol which can reduce investment costs in respect offeed equipment and storage.

The hydrolysis and the condensation and/or interesterification step,whenever applicable, use enzymes that may be the same, or may bemono/di-acyl selective enzymes.

Furthermore the enzymes are selected from phospoholipases, and lipases.The enzymes may be used in solution or can be immobilised and as suchhave an impact on the purification of the reaction medium and stabilityof the enzyme. As mentioned before, the enzyme applied in the hydrolysis(whenever needed) and the enzyme used in the interesterification canhave the same or different selectivity and likewise can have the samestability or different.

Lipases are classified according to the sources from which they areobtained, such as microorganism (fungi or bacteria), animal and plant.Most lipases applied are derived from fungal or bacterial sources. Someof the most widely used fungal lipases are derived from various specieswithin genera such as Candida, Yarrowia, Aspergillus and Penicillium,while bacterial lipases often come from Pseudomonas sp., Bacillus sp.,Staphylococcus sp., Burkholderia sp. and many others. Bacterial lipasesand esterases have been classified into eight families (and severalsubfamilies) based on sequence homology and biological properties.Lipases from animal origin have been originated from various organs andtissues of several mammalian species, among which the pancreatic lipasesare the most thoroughly studied. Plant lipases have not received thesame attention as those from other sources, but oilseed lipases havebeen of greatest interest among the plant lipases. An non-exhaustive,non-limiting list of suitable lipases includes, lipase derived fromCandida cylindracea, Candida lipolytica, Candida rugosa, Candidaantarctica, Candida utilis, Chromobacterium viscosum, Geotrichumviscosum, Geotrichum candidum, Mucor javanicus, Mucor miehei, Porcinepancreas, Pseudomonas species, specifically Pseudomonas fluorescens,Pseudomonas cepacia, Pseudomonas pseudoalkaligenes, Pseudomonasalkaligenes, Thermomyces species, Rhizopus arrhizus, Rhizopus delemar,Rhizopus niveus, Rhizopus oryzae, Rhizopus javanicus, Aspergillus niger,Penicillium roquefortii, Penicillium camembertii or an esterase derivedfrom Bacillus species, specifically Bacillus thermoglucosidasius; Mucormiehei, Horse liver, Saccharomyces cerevisiae, Pigs liver orcombinations thereof.

Phospholipases are classified as types A₁, A₂, C, and D, each withdifferent bond selectivities.

For example, the hydrolysis of palm stearin is preferably performed inpresence of a lipase, such as Lipozyme TL or Lipozyme 435 (earlier knownas Novozyme 435).

This hydrolysis may result in a composition that is containing from25-50% of free fatty acids. Decantation of up to 80% of the hydrophobicphase of the composition is followed by a condensation and/orinteresterification reaction under reduced pressure that allows theremoval of water to shift the equilibrium in presence of a lipase and itis resulting in an oily composition (oil) containing less than 0.5% freefatty acids, and from 1% to 10% mono-acylglycerides (MAG).

Specifically, palm stearin is hydrolysed in presence of 5-10% water andlipase and a hydrolysed mixture containing 25-50% of free fatty acids isformed. 50% of the hydrophobic part of the hydrolysed mixture is removedby decantation and the residual part is condensed to get an oilycomposition (oil) containing less than 0.5% free fatty acids and from 6to 10% of mono-acylglycerides. For the hydrolysis a lipase such as forinstance Lipozyme TL 100 can be used and for the condensation a lipaselike Lipozyme 435 can be applied. The composition is filtered to removethe enzyme, followed by bleaching and deodorisation. The finishedproduct is a deodorized oil comprising more than 4% w/w of in-situprepared mono-acylglycerides.

Alternatively, the triglyceride oil is hydrolysed in presence of aMAG/DAG selective enzyme that more efficiently creates free glycerol.The mixture obtained after the hydrolysis is containing from 25 to 40%free fatty acids and by decantation of less than 50% of the hydrophobicphase followed by a condensation and/or interesterification reaction ofthe remaining phase under reduced pressure, that allows the removal ofwater to shift the equilibrium, a deodorized oil containing less than 1%free fatty acids, and 6-10% mono-acylglycerides (MAG) is obtained.

Finally, the oily composition (oil) containing less than 1% w/w freefatty acids, is purified by filtering off the enzyme. Furtherpurification can be achieved through bleaching. Bleaching as such can beapplied in general or to perform removal of the remaining enzyme.

Bleaching

The nature and operation of the bleaching system will depend, at leastin part, on the nature and quality of the oily composition beingbleached. Generally, the oil will be mixed with a bleaching agent whichcombines with oxidation products, trace phosphatides, trace soaps, andother compounds adversely affecting the colour and flavour of thecomposition. As is known in the art, the nature of the bleaching agentcan be selected to match the nature of the oily composition to yield adesirable bleached glyceride containing fraction. Bleaching agentsgenerally include natural or “activated” bleaching clays, also referredto as “bleaching earths”, activated carbon and various silicates. Askilled person will be able to select a suitable bleaching agent fromthose that are commercially available.

The composition is further refined by deodorisation.

Deodorising

The deodorising process and its many variations and manipulations arewell known in the art and in the current invention a low-temperaturedeodorisation is applied. Preferably, it will include introducing theglyceride composition or the refined oily composition into a deodoriserand contacting it with steam to vaporize and drive off free fatty acidswhile maintaining the mono-acylglycerides into the glyceride containingfraction.

The deodoriser may be any of a wide variety of commercially availabledeodorizing systems, including both multi-chamber deodorisers (such asthose sold by Krupp of Hamburg, Germany; De Smet Group, S.A. ofBrussels, Belgium; Gianazza Technology s.r.l. of Legnano, Italy; AlfaLaval AB of Lund, Sweden, or others) and multi-tray deodorisers (such asthose sold by Krupp, DeSmet Group, S.A., and Crown Ironworks of theUnited States).

The deodoriser is desirably maintained at an elevated temperature nothigher than 210° C., preferably not higher than 190° C. and a reducedpressure to better volatilise the FFA. According to one possibleembodiment of the invention, the deodoriser will be maintained at apressure of no greater than 10 mm Hg. Preferably, it will be maintainedat a pressure of no greater than 5 mm Hg, e.g., 1-4 mm Hg.

The lower deodorisation temperatures provide at least two advantages:

-   -   avoiding the distillation of mono-acylglycerides, and    -   avoiding the formation of unwanted compounds such as,        epoxypropanol fatty acid esters.

The current invention relates to a deodorized oil containing 30 to 70%triglycerides, 20 to 50% di-acyl glycerides, 1.5 to 25% mono-acylglycerides. The current invention further relates to the deodorized oilwherein the mono-acylglycerides are present in an amount of from 3% to15%, more preferably from 5% to 10%. Furthermore it relates to thedeodorized oil of the current invention wherein the di-acyl glyceridesare present in an amount from 30 to 46%. More specifically, it relatesto the deodorized oil of the invention wherein the amount oftriglycerides is from 35 to 65%, the amount of di-acyl glycerides isfrom 30 to 46%, the amount of mono-acyl glycerides is from 3 to 10%.

Very specific examples are the deodorized oils containing 62%tri-acylglycerides (TAG), 33% di-acyl glycerides (DAG), 3%mono-acylglycerides (MAG), or containing 35% TAG, 45% DAG, 9% MAG, orcontaining 7% MAG, 34% DAG, 54% TAG, or containing 5% MAG, 34% DAG, and58% TAG.

The presence of in-situ prepared mono-acylglycerides has the significantadvantage that the obtained deodorized oil is emulsifying without theaddition of any foreign material. In fact no foreign material is added,while extremely low quantities of residues form the in-situ preparationare distinguishing the deodorized oils containing in-situ preparedmono-acylglycerides from existing oils that may contain mono-acylglycerides that are explicitly added to the oil.

Additionally, the deodorized oil of the current invention is low inunwanted components such as epoxypropanol fatty acid esters. Theseunwanted epoxypropanol fatty acid esters are present in an amount below500 ppb, preferably below 300 ppb, even more preferably below 150 ppb.

The deodorized oil of the current invention has all the benefits fromthe presence of a significant amount of mono-acylglycerides and absenceof free fatty acids and absence of unwanted epoxypropanol fatty acidesters.

The presence of in-situ mono-acylglycerides provides a deodorized oilwith suitable emulsifying properties and without presence of foreignmaterial that would require addition of mono-acylglycerides through anextra process step.

The invention will hereunder be illustrated in the following examples.

EXAMPLES Example 1

Palm Stearin (Low MAG)

37.5 kg Palm Stearin (Cargill Botlek) was mixed in Pilot reactor with 3l water at 70° C. 200 g Lipozyme 435 was added. After 48 h the contentof FFA was 23.7%. Stirring was stopped and after 30 minutes settling, 15kg of the upper layer were taken out from the reactor. The stirring wasstarted again, and carefully vacuum was applied to remove water andinitiate condensation. After 22 h at 50-100 mbar, FFA was 1.0%.According gel permeation chromatography (GPC), the composition was 62%TAG, 33.2% DAG, 3.4% MAG, and 0.8% FFA according titration.

Example 2

Palm Stearin (High MAG)

37.5 kg Palm Stearin (Cargill Botlek) was mixed in Pilot reactor with 5l water at 70° C. 300 g Lipozyme 435 was added. After 94 h the contentof FFA was 36.7%. Stirring was stopped and after 30 minutes settling, 16kg of the upper layer were taken out from the reactor. The stirring wasstarted again, and carefully vacuum was applied to remove water andinitiate condensation. After 29 h at 50-100 mbar, FFA was 0.99%.According gel permeation chromatography (GPC), the composition was35.25% TAG, 45.51% DAG, 8.94% MAG, and 0.96% FFA according titration.

Example 3

DAG from Short Path Evaporation (SPE) Distillate

100 g distillate fraction from a short path evaporation of RBD Palm Oilwith 1.8% MAG, 49% DAG, 42% TAG was interesterified under vacuum using1% Lipozyme TL IM. After 48 h product was isolated by filtration.Composition of the final material was 6.5% MAG, 34% DAG, 54% TAGaccording Gel Permeation Chromatography with FFA of 0.23% accordingtitration.

Example 4

DAG from SPE Distillate

100 g distillate fraction from a short path evaporation of RBD Palm Oilwith 1.7% MAG, 48% DAG, 47% TAG was interesterified under vacuum using1% Lipozyme 435. After 48 h product was isolated by filtration.Composition of the final material was 5.3% MAG, 33.5% DAG, 58% TAGaccording Gel Permeation Chromatography with FFA 0.58% accordingtitration.

1-15. (canceled)
 16. A deodorized oil comprising 35 to 65% w/wtriglycerides, 20 to 50% w/w di-acyl glycerides, and 1.5 to 25% w/wmono-acyl glycerides.
 17. The deodorized oil according to claim 16,wherein the mono-acylglycerides are present in an amount of from 3% to15% w/w.
 18. The deodorized oil according to claim 16, wherein themono-acylglycerides are present in an amount of from 5% to 10% w/w. 19.The deodorized oil according to claim 16, wherein the di-acyl glyceridesare present in an amount from 30 to 45% w/w.
 20. The deodorized oilaccording to claim 16, wherein the amount of triglycerides is from 35 to60%, the amount of di-acyl glycerides is from 30 to 45%, and the amountof mono-acyl glycerides is from 3 to 10% w/w.
 21. The deodorized oilaccording to claim 16, wherein the deodorized oil contains less than 1%w/w free fatty acids.
 22. The deodorized oil according to claim 16,wherein the amount of free fatty acids is less than 0.1% w/w.
 23. Thedeodorized oil according to claim 16 further comprising an amount below500 ppb of unwanted epoxypropanol fatty acid esters.
 24. A deodorizedoil comprising 35 to 60% w/w triglycerides, 30 to 45% w/w di-acylglycerides, 3 to 10% w/w mono-acyl glycerides, and less than 0.1% w/wfree fatty acids.
 25. The deodorized oil of claim 24 further comprisingan amount below 500 ppb of unwanted epoxypropanol fatty acid esters.